The present invention relates generally to a data storage and retrieval system, and in particular to a data storage and retrieval system utilizing portable data storage cartridges, each of which includes data position information stored within a memory device, in combination with memory reading devices disposed on one or more accessors movably disposed within that data storage and retrieval system. The present invention further relates to a method to communicate such position information relating to a specified portable data storage cartridge to a data drive in advance of the arrival of that specified portable data storage cartridge to expedite data acquisition from that specified portable data storage cartridge.
The need to store and retrieve large volumes of digital data has resulted in the need for data storage devices having ever increasing amounts of storage capacity. Data can be stored, of course, in cassettes, floppy disks, diskettes, hard disks, optical disks, capacitative disks and the like. However, the greater the amount of memory available, the more difficult it becomes to accurately obtain specified data with rapid access times and with maximum system fault tolerance.
Automated data storage and retrieval systems, more commonly known as libraries, jukeboxes or auto changers (collectively referred to herein as xe2x80x9clibrariesxe2x80x9d), are frequently used when there is a need to keep relatively large amounts of data available at a cost per gigabyte which is lower than that of solid state memory or hard files. Libraries are available for optical disks, optical tape and magnetic tape media. The optical disks can be, for example, rewritable magneto-optical, rewritable phase change, write-once (WORM), standard CD-ROM, recordable CD-ROM, erasable CD-ROM or high density CD-ROM. Magnetic tape, optical tape, and optical disks (one or more), are often disposed within a rigid protective housing comprising a cassette or a cartridge. Some libraries store and transport xe2x80x9cmagazinesxe2x80x9d containing several media-containing cartridges. As used herein, unless otherwise specified, the term xe2x80x9cmediaxe2x80x9d will refer to any data storage media by itself, and the term xe2x80x9ccartridgexe2x80x9d will refer to any portable data storage device having a data storage media internally disposed therein.
Prior art systems sometimes utilize a plurality of data storage media in conjunction with one or more robotic accessors to retrieve stored cassettes and place them in data drive unit. For example, portable data storage cartridges are transported from a storage area to a data drive mechanism which reads and/or records data for utilization by a host computer from and/or to the data storage media disposed within those cartridges. After the data drive unit, and its associated drive controller, have completed use of the data storage media, the portable data storage cartridge is returned to its storage area. The time expended to transport the cartridge from the storage area to the data drive mechanism is lost in prior art system because the cartridge is transported with very little, if any, retrieval of the data position information from the media disposed in the cassette.
A typical library contains one or more banks, columns, or walls of storage cells, one or more data drive units, and one or more accessors to transport specified portable data storage cartridges between those storage cells and data drives. Each accessor generally includes a hand-like gripper mechanism to remove and/or insert the portable data storage cartridges to and from a storage cell, and to and from a data drive unit. The library may also include an input/output station through which an operator can insert or withdraw data units into and from the interior of the library.
The components of a library are coupled to and controlled by a library controller which in turn is coupled to a host computer. Data requests are exchanged between the host computer and the library controller, and between the library controller and the other components of the library system. Data written on, or retrieved from, storage media disposed in portable cassettes is exchanged between the host computer and the drive controller.
In many prior art libraries, the cassettes (cartridges) have a machine readable label on a front facing edge which is visible when the cartridge is in a storage cell. A reader, such as a vision system or bar code scanner is mounted on the accessor. The reader senses the label to verify that a particular cartridge is the cartridge which has been specified. Such a system is shown in U.S. Pat. No. 5,729,464, issued on Mar. 17, 1998 to K. E. Dimitri, entitled xe2x80x9cMedia Identification In An Automated Data Library,xe2x80x9d and assigned to the assignee of the present invention. Only a very limited amount of data, however, can be retrieved from such a label. In addition, that limited information is not changeable unless the entire label is replaced.
What is needed is an apparatus and a method to enable a data storage and retrieval system to obtain data position information from a specified portable data storage cartridge, and to provide that data position information to a data drive unit before arrival of that specified data storage device, i.e. while an accessor is transporting that portable data storage cartridge to the drive.
Applicants"" invention includes a portable data storage cartridge which includes a memory device disposed therein and data position information stored on that memory device. Applicants"" invention further includes an accessor for retrieving and transporting Applicants"" portable data storage cartridge within a data storage and retrieval system. Applicants"" accessor includes one or more gripper mechanisms and a memory reading device disposed thereon such that when one of Applicants"" portable data storage cartridges is releaseably attached to any of the gripper mechanisms the accessor""s memory reading device is disposed adjacent the cartridge""s memory device.
Applicants"" invention further includes a method to expedite access to data stored on a data storage media disposed within Applicants"" portable data storage cartridge. Applicants"" invention further includes a computer useable medium having computer readable program code disposed therein to implement Applicants"" method to expedite data retrieval from a portable data storage cartridge.
The foregoing and other features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings.